THE ROLE OF LIFE-STYLE FACTORS IN THE ETIOLOGY OF STROKE - A POPULATION-BASED CASE-CONTROL STUDY IN PERTH, WESTERN-AUSTRALIA

Background and Purpose We sought to examine risk factors for all strok es and for ischemic stroke and primary intracerebral hemorrhage separa tely. Methods This was a population-based case-control study. Each cas e subject meeting World Health Organization criteria for stroke (n=536 ) from a population-based register of acute cerebrovascular events com piled in Perth, Western Australia, in 1989 to 1990 was matched for age and sex with up to five control subjects drawn from the same geograph ical area. Objective confirmation of the type of stroke was available from computed tomography, magnetic resonance imaging, or necropsy for 86% of the case subjects. Data on medical history and lifestyle factor s were collected from case and control subjects by interview of the su bject or a proxy informant. Results Current smoking, consumption of me at more than four times weekly, and a history of hypertension or inter mittent claudication were each associated with increased risk in multi variate models for all strokes and for all first-ever strokes. Consump tion of 1 to 20 g/d alcohol in the preceding week was associated with a significant reduction in the risk of all strokes, all ischemic strok es, and of primary intracerebral hemorrhage, while eating fish more th an two times per month appeared to protect against first-ever stroke a nd against primary intracerebral hemorrhage. Diabetes mellitus was ass ociated with a significantly increased risk of ischemic stroke but a d ecreased risk of hemorrhagic stroke. Conclusions Risk factors for isch emic and hemorrhagic stroke are not exactly the same. Changes in lifes tyle relating to tobacco and diet might make important contributions t o further reductions in the incidence of stroke.